Pediatric brain tumor survivors (PBTS) suffer from cognitive late effects, such as deteriorating executive functioning (EF). We explored the suitability of the Behavior Rating Inventory of Executive Function (BRIEF) to screen for these late effects. We assessed the relationship between the BRIEF and EF tasks, and between the BRIEF-Parent and BRIEF-Teacher, and we explored the clinical utility. Eighty-two PBTS (8–18 years) were assessed with EF tasks measuring attention, cognitive flexibility, inhibition, visual-, and working memory (WM), and with the BRIEF-Parent and BRIEF-Teacher. Pearson’s correlations between the BRIEF and EF tasks, and between the BRIEF-Parent and BRIEF-Teacher were calculated. The BRIEF-Parent related poorly to EF tasks (rs < .26, ps > .01), but of the BRIEF-Teacher the WM-scale, Monitor-scale, Behavioral-Regulation-Index, and Meta-cognition-Index, and Total-score (rs > .31, ps < .01) related significantly to some EF tasks. When controlling for age, only the WM scale and Total score related significantly to the attention task (ps < .01). The inhibit scales of the BRIEF-Parent and BRIEF-Teacher correlated significantly (r = .33, p < .01). Children with clinically elevated scores on BRIEF scales that correlated with EF tasks performed worse on all EF tasks (ds 0.56–1.23, ps < .05). The BRIEF-Teacher Total and Index scores might better screen general EF in PBTS than the BRIEF-Parent. However, the BRIEF-Teacher is also not specific enough to capture separate EFs. Solely relying on the BRIEF as a screening measure of EFs in BPTS is insufficient. Questionnaires and tasks give distinctive, valuable information.